VisionSet wrote:
Is there anything I can do to improve the finish of set concrete. I
want a smooth finish and I have got that for most of the surface but
in a few places it is acceptable but could do with being smoother.
Concrete is still fresh so it is not as hard as it will be in the
hours and days to come. It's a window sill.

Strong sand & cement? - I'd use fine building sand rather than grit sand,
although I wouldn't bother with it yet as it will probably need facing up
once the box comes off.

We always used to use granno instead of concrete for sills, it's much finer
and packs down better and leaves a better finish.